Nearly 3,000 civilians escaped from Sri Lanka’s war zone and sought shelter with security forces, the defence ministry said Sunday as troops stepped up an offensive against cornered Tiger rebels.

Nearly 3,000 civilians escaped from Sri Lanka’s war zone and sought shelter with security forces, the defence ministry said Sunday as troops stepped up an offensive against cornered Tiger rebels.

The non-combatants escaped Saturday evening from the remaining area under the control of the Liberation Tigers of Tamil Eelam (LTTE), the ministry said in a statement.

“The civilians started arriving in large groups since (Saturday) afternoon using the safe routes opened for them by troops,” the ministry said.

The influx into government-held territory was in contrast to the trickle of civilians that came through when the military observed a unilateral two-day truce earlier in the week, the ministry noted.

Security forces kept up their offensive against Tamil Tiger rebels trapped in a government-declared “no-fire zone,” ignoring international appeals for a ceasefire.

At least 17 rebels were killed and another 22 wounded in fighting Saturday, the government said.

“Battlefield reports indicated that troops have encountered stiff resistance from the terrorists,” it said.

President Mahinda Rajapakse told party workers at his tightly guarded residence in Colombo Saturday that the decimated Tamil Tigers faced a stark choice.

“They have only three alternatives. Either they have to surrender to our armed forces, eat the cyanide capsule (worn round their necks) and commit suicide, or plunge into the sea,” he said.

Rajapakse said the international community should stop putting pressure on him for another ceasefire and instead ask Tiger rebels to free civilians in the conflict zone.

The United Nations says up to 100,000 civilians are trapped in the area in “dire humanitarian conditions.”

The government has accused the Tigers of holding the civilians as a human shield, a charge denied by the guerrillas, who are trying to prevent a total defeat after fighting for 37 years for a separate state.

UN chief Ban Ki-moon last week sent his chief of staff, Vijay Nambiar, for talks with Sri Lankan leaders to extend the ceasefire but was rebuffed, officials said.

Britain’s Foreign Secretary David Miliband said at the weekend he would ask Nambiar to report to the UN Security Council “immediately” on his return.

“I remain gravely concerned at the continuing conflict in northern Sri Lanka that threatens many thousands of civilian lives,” Miliband said in a statement.

“The British government maintains its calls for an immediate ceasefire in Sri Lanka and for civilians to be allowed to leave the conflict area.”

He added that that Prime Minister Gordon Brown’s special envoy on Sri Lanka, former defence secretary Des Browne, was travelling to New York “to consult urgently with the UN.”

Last Saturday, an estimated 100,000 people joined a Tamil protest in London calling for a ceasefire.